In semiconductor device manufacturing, capacitors are passive circuit components that are utilized in integrated circuitry of a semiconductor chip for various purposes. For example, capacitors can be utilized to decouple power supplies, to form memory elements, to form RC delay circuits, or provide various other circuit functions. While many types of capacitor structures can be utilized, MIM capacitors are commonly used for analog, microwave, and radio frequency (RF) applications. In general, planar MIM capacitors are comprised of two metallic plates separated by an insulator layer. As is known in the art, the capacitance of an MIM capacitor is (i) directly proportional to a surface area of the overlapping metallic plates, (ii) directly proportional to a dielectric constant of the dielectric material of the capacitor insulator layer, and (iii) inversely proportional to a thickness of the capacitor insulator layer.
MIM capacitors with high cutoff frequency are desired for decoupling of power supplies with mid and high-frequency noise. In particular, high-performance circuits typically require high-value, low-impedance decoupling capacitors between direct current (DC) power supply lines and ground metal lines to limit noise created by rapid switching of current within an integrated circuit, and to prevent voltage drops that occur when MIM capacitors have low transient response times, e.g., τ=R×C (e.g., low cut-off frequencies) and cannot supply the proper charge in response to the rapid switching of current within the integrated circuit. When the voltage drop is significant, the integrated circuitry will not function properly.